000 WTNT41 KNHC 300242 TCDAT1 Hurricane Oscar Discussion Number 13 NWS National Hurricane Center Miami FL AL162018 1100 PM AST Mon Oct 29 2018 The satellite presentation of Oscar continued to improved after the release of the previous advisory, with the small eye becoming a little more distinct around 0000 UTC, but it has again become cloud filled within the past hour or so. Recent microwave imagery continues to depict a tiny eye with a solid ring of deep convection surrounding it, but there is little outer banding over the southwestern portion of the circulation likely due to shear and dry air. Objective satellite intensity estimates which may be having trouble discerning the small eye are around 80 kt, while subjective T-numbers range from T5.0 from SAB to T5.5 from TAFB. As a result, the initial intensity has been increased to 90 kt for this advisory. Although the NHC intensity forecast does not explicitly show additional strengthening, Oscar has another 12 hours or so over SSTs of 26-26.5 deg C in which some slight intensification could occur. After that time, increasing southwesterly shear and cooler waters along the forecast track should cause the hurricane to weaken gradually as extratropical transition begins. Oscar is forecast to complete extratropical transition in about 48 hours, and remain a powerful post-tropical cyclone over the north Atlantic for much of the forecast period. The global models indicate that Oscar's wind field will quickly expand during its transition to a post-tropical cyclone, and this is reflected in the NHC wind radii forecast. The hurricane has been moving slightly east of due north or 010/8 kt. Oscar is forecast to begin to accelerate north-northeastward or northeastward ahead of a deep-layer trough that will be moving over the western Atlantic on Tuesday. The hurricane should be well embedded within the deep-layer southwesterly flow ahead of the trough by Tuesday night or Wednesday, and the cyclone is expected to move rapidly northeastward across the north-central and northeastern Atlantic later this week. There has been little change to the guidance envelope, and the new NHC track forecast is essentially an update of the previous advisory. The official forecast again lies near the various consensus aids and is near the middle of the tightly clustered model guidance. Although Oscar is not expected to directly affect any land areas, large swells from Oscar will affect Bermuda through Wednesday. Please consult products from your local weather office as these conditions could cause life-threatening surf and rip currents. FORECAST POSITIONS AND MAX WINDS INIT 30/0300Z 27.4N 58.3W 90 KT 105 MPH 12H 30/1200Z 28.8N 57.7W 90 KT 105 MPH 24H 31/0000Z 31.5N 55.6W 85 KT 100 MPH 36H 31/1200Z 35.3N 52.1W 80 KT 90 MPH 48H 01/0000Z 40.1N 47.8W 70 KT 80 MPH...POST-TROP/EXTRATROP 72H 02/0000Z 49.1N 36.4W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 03/0000Z 56.2N 22.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 04/0000Z 62.5N 9.5W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown